Charge forming device



May 23, 1933. F. E. ASELTINE 1,910,421

CHARGE FORMING DEVICE Filed Sept. 16; 1929 3 Sheets-Sheet 1 az v Jig. Z.

May 23, 1933. F. E. ASELTINE 1,910,421

CHARGE FORMING DEV ICE Filed e t. 16, 1929 3 Sheets-Sheet 2 Q gwvvntor,

I M akai. $041.4, %MW,JM -M 49% May 23, 1933, F. E. ASELTINE' CHARGEFORMING DEVICE Filed Sept. 16, 1929 3 Sheets-Sheet wmww Patented May 23,1933 UNITED STATES PATENT OFF FRED E. ASELTINE, 0F DAYTON, OHIO,ASSIGNOR T0 DELCO PRODUCTS CURPOMTIGN, OF DAYTON, QHIO, A CORPORATION OFDELAWARE CHARGE FORMING DEVICE Application filed September 16, 1929.Serial No. 392,909.

This invention relates to charge forming devices for internal combustionengines, and more particularly to devices of this character whichcomprise a plurality .of primary carburetors which deliver a primarymixture of fuel and air to a plurality of secondary mixing chamberslocated adjacent the engine intake ports, and in which the primarymixture is mixed with additional air under certain operating conditions.

A device of this character is disclosed in the co nding application ofFred E. Aseltine, erial No. 286,975, filed June 20, 1928, to whichreference may be had for a full disclosure of the devicedescribedherein.

The principal object of the present invention is to provide novel meansfor temporarily enriching the mixture during the acceleration periodimmediately following any opening movement of the throttle and moreparticularly, to provide a device of this character which is effectiveonly after opening movements of the throttle, which take place when theengine is operating at speeds above a certain predetermined speed. 1

The device disclosedin this application is similar to that disclosed inthe above mentioned copending case, and differs therefrom only in thefact that such case discloses a fuel pump operated by the primarythrottle and which is effective to pump fuel on every opening movementof said throttle, while the device disclosed in this application comprises a pump which is operated by the secondary or air throttle and is,therefore, effective to pump fuel into the mixing chambers only onopening movements of said air throttle. In devices of this character,the air throttle does not open until the engine is operatin at apredetermined speed, generally a spec corresponding to a vehicular speedof from 15 to 25 miles per hour.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawings:

Fig. l is a fragmentary, plan'view of a charge forming device in whichthe present inventlon is embodied.

Fig. 2 is a side elevation of the carburetor unit forming part of thedevice.

Fig. 3 is a longitudinal section through a charge forming deviceembodying the pres-- entinvention and an engine intake port with whlchsuch device is associated.

Fig. 4 is a transverse section on'the line 4F4 of Fig. 3.

1g. 5 is a fra entar transve se'section on the line 5-5 lii 3. g I IFig. 6 is a plan view of the entire charge formm device.

The evice disclosed comprises a main air manifold 10 having three outletbranches, the middle branch 12 being shown herein. Each of thesebranches communicates with one of the intake orts 14 of agmulticylinderengine. The out et branches are each provided with an attaching flange16 for securmg the manifold to the engine block in the usual manner anda flange 18 to which the carburetor unit is secured. I The carburetorunit comprises a main housmg 20, having an attaching flange 22, adaptedto be. secured to the flange 18 b screws 24. An air inlet coupling 28 issecured in position to register with an opening in the upper wall of thehousing 20, in any suitable way and may be connected with an air cleaner1f desired. A casting. 30, in which the passages and the flow of fuel tothe bowl is controlled by a float 36, operatin in the usual manner tomaintain a substantially constant level of fuel therein.

Fuel flows from the bowl 32 to a plurality of primary fuel nozzles 38,one of which is located in each of the primary mixing chamhers 40, theconstruction of which is brlefly described hereinafter. The fuel conduitbe tween the fuel bowl and the nozzles comprises the vertical fuelpassage 42 communicating at its upper end with the horizontal fuel canal44, which connects with each of the nozzles 38 through an orifice 46.Fuel is admitted from the fuel bowl to the passage 42 ;f throttle causea reduction in mixing chamber suction which might permit the fuel columnto drop sufiiciently to cause a temporary fuel starving of the engineunless means are provided to prevent this action. For this purpose acheck valve 54 is provided in an enlarged chamber 56 at the junction ofthe chan-' nels 42 and 44, and on reduction of mixing chamber suction,seats on the bottom of the chamber, preventing downward flow of fuel.

Each primary fuel nozzle is provided with a main fuel outlet 58 in thetop of the nozzle and a secondary fuel outlet comprisingtwo orifices 60and 62 in the vertical wall of the nozzle near the bottom of the mixingchamber. At'relatively high speeds, the mixing chamber suction issufiicient to lift fuel from the main outlet as well as from orifices 60 and 62. At idling, or low speed operation under load, however, thesuction is enough to lift fuel only to some point between the top of thenozzle and the orifices 60 and 62, fuel flowing fromthese orifices bythe action of gjravity under such operating conditions.

ach nozzle is provided with a restricted fuel metering orifice 63. Theprimary mixingchambers comprise the enlarged anterior ends of theprimary mixture passages 64, which are parallel to each other and closetogether, as indicated in Fig. 4. When the carburetor is attached to themanifold, these' passages registerwith conduits which convey the primarymixture to the secondary mixing chambers, as fully disclosed in theapplication above referred'to. Restrict-ions 66 separate the primarymixing chambers from the remainder of the mixture passages to reduce thevelocity of flow past the fuel nozzles for a pur ose fully set forth inthe above mentione copending application.

A sin le throttle valve 68, which extends across a theprimary mixturepassages, controls the flow therethrough and is provided with grooves70, which register with said mixture passages. This throttle is operatedin a manner hereinafter more fully described. The middle primary mixturepassage communicates with a tube 72 fixed in the manifold C3 branch 12.This tube constitutes one of the primary mixture conduits above referredto and conveys the primary mixture to the secondary mixing chamberlocated in themiddle branch of the manifold.

Nearly all of the air entering the carburetor flows through the inletcoupling 28 and is controlled by the main air valve 74, normally heldagainst a seat 76 by a spring 78, received between the valve and aflange 80, projecting from a sleeve 82, slidably mounted on a stationaryguide sleeve 84, fixed in the housing 20, and serving also as a guidefor the stem 86 to which the air valve is secured. When it'is desired tochoke the carburetor to facilitate starting of the engine, the flange 80is adapted to be lifted by means not shown herein, but fully describedin the above application, until the upper end of the sleeve 82 engagesthe air valve to hold it closed. Suflicient air to carry the startingfuel from the nozzles to the intake ports is admitted through anelongated slot 87, formed in a plate 88, secured to the housing 20, asshown in Fig. 3.

' The valve 74 admits air to the air chamber 90, from which air flowsto'the primary mixture passages through an orifice 92 in the bottom ofthe air chamber and to the secondary mixing chambers through a passage94, which connects with the inlet of the manifold 10. The flow of airthrough this passage is controlled by'a manually operable throttle 96,secured to a shaft 97, rotatably mounted in the main housing.

The operating connections for the throttle valves comprise an operatingarm 98 provided with an orifice 100 in its free end, in which somesuitable form of operating connection extending to a point convenient tothe operator of the vehicle isadapted to be secured. This arm is securedin any desirable manner to a spindle 102, projecting from the end of theprimary throttle and is connected by a lost motion connection,hereinafter described spccifically, to an arm 104, secured to the shaft97 by a split clamp or other suitarm 98 and provided with a slot 108through which a pin 110, screwed into the arm 104, projects. Aregulating screw 112 isthreaded in lugs 114, projecting from the link,and

may be adjusted to regulate the length of the slot 108 the upper end ofsaid screw constituting the lower end of the slot. A tension spring 116is connected at one end to the upper end of the link and at the otherend, to the pin 110. This spring tends to hold the pin against the upperend of the slot 108 but with both throttles closed, the parts are in theposition shown in Fig. 2, with the pin 110 in engagement with theregulating screw 112. As the operating arm 98 is rotated in acounter-clockwise direction to open the primary throttle the link 106moves downwardly to a position where the upper end of the slot 108strikes the pin 110 before the operating arm 104 of the air throttle ismoved, so that the primary throttle is partly opened before the airthrottle begins to move. The screw 110 operates as a stop to limit theclosing movement of the primary throttle and adj ustnient of the screwregulates the position of the primary throttle at idling. The abovedescribed lost motion connection is generally so adjusted that theprimary throttle 1s opened to a position permitting an engine speedcorresponding to a vehicular speed of 15 to 25 milesper hour on a levelbefore the air throttle starts to open.

On opening of one or both of the throttle valves, the suction in the airchamber 90 s increased and the valve 74 is opened to admit additionalair and increase the quantity of mixture supplied the engine. The 0 ofthis valve is retarded to prevent uttering thereof and to restrict theadmission of air to prevent a temporary leaning of the mixture wheneverthe throttles are opened. To this end a dashpot is provided WhlC-l'lcomprises a cylinder 120, receiving fuel from the reservoir 32 and apiston 122, secured to the lower end of the valve stem 86 by anysuitable means. Fuel is admitted tothe cylinder on closing movements ofthe air valve by a check valve (not shown) which also operates toprevent escape of fuel therefrom when the valve is open; The specificconstruction of this dashpot forms no part of this invention and it maybe of any conventional form.

As hereinbefore stated, additional fuel is supplied to the mixingchambers following any openlng movement of the air throttle 96. To thisend a pum is provided com rislng a cylinder 130 cast integral with theashpot cylinder 120, as shown in Fig. 4, and having its lower end closedby a removable lug 132. A pump piston 134 is slidable within thecylinder and is connected by a piston rod 136 to a link 138, which ispivotally connected at 140 to said rod and at 142 to the free end of anoperating arm 144', secured to the shaft an enlargement 148 in which isreceived a passage 146 check valve 150,.which closes the on downwardmovement'of the iston.

Reduced portion 152 of the p 11g 132 projects downwardly therefrom andis provided with a central bore 154 normally closed'by cap 156 screwedon the part 152. A restricted orifice 158 connects the bore 154 with theinterior of the pump cylinder and a fuel delivery conduit 160 isreceived in an orifice in the wall of the reduced portion of the plugning 152 and communicates withsaid bore 154. The flow'of fuel from thepump cylinder to the delivery conduit is controlled by a valve 162,connected by a wire 164 to a small piston 166, slidably received withina recess 168 formed within the main pump piston. A spring 170 surroundsthe wire between the bottom of the piston 166 and the plug 132 normallyholding the valve 162 in position to close the orifice 158, as will bemore fully described hereinafter.

The fuel delivery conduit extends through that portion of the mainhousing which constitutes the top of the float bowl, as indicated inFig. 4, and immediately above the bowl,

be provided in each of the pipes 174, 176 and 17 8, if desired. Thesepipes, at their delivery ends, are bent upwardly as indicated in Fig. 3,and extend obliquely through the attaching flange 16 and the walls ofVenturi tubes 180, which form the secondary mixing chambers, terminatingflush with'the lower surface of said Venturi tubes at a pointsubstantially adjacent the point of greatest suction therein. The pumdelivery conduits could, obviously, exten into. the Venturi tubes ratherthan terminate flush with the wall, but if so constructed, would tend toproduce some disturbances in the air flow ad- Jacent the delivery endsof the primary mixture conduits, whichmight effect the operation of thedevice to some extent by reason o'f eddy currents. For this reason, theconstruction disclosed herein is deemed more desirable.

It will be clear that the suction and the rate of flow through theVenturi tubes at the point where the pump delivery conduits terininateis at all times high and when the main air throttle "is opened, thevelocity-of flow through these tubes is particularly great. Owing to thepresence of a high degree of vacuumand high air velocity at the outletsI from thesev delivery conduits, the fuel issuing therefrom will bepartly vaporized and the unvaporized particles which remain will bethoroughly mixed with the mixture passing through the tubes.

The construction of the above described pump mechanism is the same asthat disclosed in the earlier copending application,

except for the fact that the pump piston is operated in this device bythe main air throttle, while in the earlier device, is operated directlyby the primary throttle. For 'a fuller disclosure of this mechanism,particutons 134 and166 so that when the pump pispum ton moves veryslowly this: leakage is suflilarly the delivery conduits, reference maybe had to such earlier application.

The secondar mixing chambers comprise the Venturi tu to, there beingthree of these which are identical in construction and when the deviceis assembled, are held in position by engagement of a rib 182, formed onthe outer surface of the venturi between shoulders 184 and 186 on themanifold and engine block respectively.

The operation of the above described pump issubstantially as follows:During the first part of the opening movement of the primary throttle,thepump is ineffective, but on any opening movement of said throttlewhich is accompanied by a relatively rapid opening movement of the airthrottle, the pump piston is moved downwardly and the pressure on thesmall piston 166 is suflicient to open the valve 162, which is normallyclosed, substantially simultaneously with the beginning of the movementof the pump piston. The valve 166 is closed at the end of any pumpstroke of the pump piston and is held closed by the spring 170 duringany upward movement of said piston so that the fuel in the deliveryconduits can not return to the pump cylinder and also, the closing ofsaid valve prevents the suction in the Venturi tubes 180 operating todraw fuel from the delivery conduits during normal operation. Thedelivery conduits are, therefore, kept full of fuel which is injectedinto the secondary mixing chambers substantially simultaneously with thebeginning of any relatively rapid opening movement'of the air throttle,and

' such fuel being supplied adjacent the engine intake ports, is carriedinto the engine cylinders without perceptible delay. During very slowopening movement of the throttle, the inection of additional fuel intothe mixture is not desirable and the valve 162 renders the pumpineffective under such conditions. There is a, slight leakage of fuelpast the piscient to prevent the building up of suflicient pressure onthe piston 166 to collapse the spring 170 and open the valve.

As previously pointed out, the device disclosed herein differs from thatdisclosed in the above referred to copending application only in themeans for operating the pump piston. It has been determined that during1 operation at all speeds under that speed at which the air throttlebegins to open, it is not altogether desirableto supply additional fuelto the mixture following an opening movement of the primary throttle.Under suchpperating conditions, the suction within the primary mixingchambers is suficient to draw suflicient fuel from the nozzles to form amixture having the desired fuel con- 180, previously referred tent andthe velocity of flow through the primary mixture conduits when the airthrottle when the air throttle is opened to admit secondary air.

While the form of embodiment of the present invention as hereindisclosed, constitutes a-preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow. 2 2

What is claimed is as follows:

1. A charge forming device for internal combustion engines comprising amixture passage, means supplying fuel and air thereto, a mixturethrottle, a secondary air passage supplying air to said mixture passage,a manually operable air throttle controlling the flow of air throughsaidsecondary passage, and means operated by said air throttle forenriching the mixture oni opening movements thereof.

, 2.-A charge forming device for internal combustion engines comprisinga mixture passage, means supplying fuel and air thereto, a mixturethrottle, a secondary air passage supplying air to said mixture passage,a manually operable air throttle controlling the flow of air throughsaid secondary passage, a fuel pump for supplying additional fuel tosaid mixture passage and a common operating means for said air throttleand the fuel P- 3. 'A charge forming device for internal combustionengines comprising a secondary mixing chamber, a primary mixture passageadapted to deliver a primary mixture of fuel and air thereto, means forsupplying fuel and air to said primar mixture passage a mixture throttlecontro the flow of primary mixture, a secondary air passage sup-- plyingair to'said secondary mixing chamber,

temporarily lean the mixture, which occurs a manually operable airthrottle for regulating the flow through said air passage, and means forenriching the mixture only on opening movements of the air throttle.

4. A charge forming device for internal.

combustion engines comp a secondary mixing chamber, a primary mixturepassage adapted to deliver a primary mixture of fuel and air thereto,means for supplying fuel and air to said primary passage a mixturethrottle controlling the flow of primary mixture, a secondary airpassage supplying air to said secondary mixing chamber, a manuallyoperable air throttle for regulating the flow through said air passage,and a pump for supplying additional fuel to the mixture only on openingmovements of the air throttle.

5. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air thereto, means for supplying fuel andair to said primary mixture passage a mixture throttle controlling theflow of primary mixture, a secondary air passage supplying air to saidsecondary mixing chamber, a manual- 1 operable air throttle forregulating the fibw through said air passage, and a pump for supplyinadditional fuel to the secondary mixing chambers only during operationof the air throttle.

6. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primary mixture passage adapted to deliver aprimary mixture of fuel and air thereto, means for supplying fuel andair to said primary mixture passage a mixture throttle controlling theflow of primary mixture, a secondary air passage supplying air to saidsecondary mixing chamber, a manual- 1 operable air throttle forregulating the ow through said air assage, a "pump for supplyinadditional uel to the secondary mixing 0 ambers and an o cratingconnection for said pump extending to the air throttle.

7. A charge forming device for internal combustion engines comprising asecondary mixing chamber, a primarymixture passage adapted to deliver aprimary mixture of fuel and air thereto, means for supplying fuel andair to saidprimary mixture; passage, a

' secondary throttle controlling admission of air to said secondarymixin chamber, a primary throttle controlling t e flow through saidprimary mixture passage, a fuel um for supplying additional fuel toenric the mixture, means throttle durin onl a part of the openingmovement of t e prlmary throttle, and means for operating the pump onlyduring opening movement 0 the secondary throttle.

8. A charge forming device for internal combustion engines comprising amixture passage adapted to supply a combustible mixture to the. intakeport of the engine,

means for supplying fuel and air to said passage, a throttle therein, asecondary air passage adapted to supply additional air to said passageat a point ad acent said intake port, an air throttle for regulating theflow through said assage, and means for supplying additiona fuel at thepoint where secondary air is mixed with, the primary mixture, said' foroperating the secondary means being-operated only during the openingmovement of said air throttle.

9. A charge'forming device for internal combustion engines comprising amixture passage adapted to supply a combustible mixture to the intakeport of the engine means for supplyin fuel and air to sai passage, athrottle t erein, a secondary air passage adapted to supply additionalair to said passage at a point adjacent said intake port, an airthrottle for regulating the flow through said passage, and a pumpconnected with the air throttle for operation thereby, and adapted tosupply additional fuel at the point Where secondary air is mixed withthe primary mixture.

10. A charge forming device for internal opening movements of thesecondary throttle for supplying additional fuel to the secondary mixingchambers simultaneously.

11. A charge forming device for internal combustion engines comprising aplurality of secondary mixing chambers, a plurality of primary mixturepassages adapted to deliver a primary mixture of fuel and air to saidsecondary mixing chambers, a secondary air passage adapted to supplyadditional air to all of said secondary mlxing chambers, an

air throttle therein controlling the-flow of air therethrough, a fuelpump, a branched delivery conduit extending from said pump to allof saidsecondary mixing chambers to suppl additional fuel theretosimultaneously an means for operating said pump only on openingmovements of the air throttle.

12. A charge forming device for internal combustion engines comprising amixture p passage, means supplying fuel and air thereto, a mixturethrottle, a secondary air passage Iplying air to said mixture throttle,a mansu ua y-operat'ed air throttle controlling the Ill flow of airthrough saidair passage a fuel pump operated by said air throttle forsupplying additional fuel to the mixture passage uring the accelerationriod, and means for rendering the pump e ective when'the air throttle isopened rapidly, but rendering the pum inefiective when the throttle isopened slow said means comprising a valve operated ythe umppiston onrelatively rapid movementst ereof.

13. A charge forming device for internal secondary 'mixing chamber, amanually operable air throttle controllingthe flow of air through saidair passage, a fuel pump operated by said air throttle for supplyingadditional fuel to the secondary mixing chamber, a delivery conduit forconveying fuel from said pump to the secondary mixing chamber and meansfor maintaining said delivery conduit full of fuel at all times.

14. A charge forming device for internal combustion engines comprising,a primary mixture passage, means for supplying fuel and air thereto, asecondary mixing chamber into which said mixture passage delivers, amixture throttle controlling the mixture flow a secondary air passagesupplying air to sai secondary mixing chamber, a manually .operable airthrottle controllin the flow of air through said air passage, a uel umpoperated by said air throttle for supp ying additional fuel to thesecondary mixing chamber, a delivery conduit for conveying fuel fromsaid pump to the secondary mixing chamber and a single means forcontrolling the flow of fuel from the pump and for maintaining thedelivery conduit full of fuel at all times.-

15. A charge forming device for internal combustion engines comprising amain air manifold communicating with the engine in take ports aplurality of secondary mixing chambers formed therein adjacent saidports, an air inlet supplying air to the manifold, a plurality ofprimary mixture passages adapted to deliver a rimary mixture of fuel andair to the secon ary mixing chambers, a mixture throttle a secondary airpassage for conveying air from said inlet to the secondary mixingchambers and means operated by the air throttle on opening movementsthereof, for supplying additional fuel to all of the secondary mixingchambers simultaneously,

to enrich the mixture during the acceleration period.

16. A charge forming device for internal combustion engines comprising asecondary combustion engines comprising, a mixture mixing chamberlocated adjacent to the engine intake port, a relatively remote rom thesecon ary mixing chamber, a primary mixture passage connecting saidchambers, means for supplying fuel and air to said mixture assage, amixture throttle controlling the ow of primary mixture, a secondary airaewage supplying additional air to the secon ary mixin chamber amanualloperable air throttle or controlling the a mission of said additionalair and means operated by the air throttle for supplying additional fueldirectly to the sec-' ondary mixing chamber on o ening movements of saidthrottle to enric the mixture for acceleration.

17 A charge forming device for internal rimary mixin chamber theretoanda pump for sup valve normally closing said outlet, and means operatedby the pump piston for opening said valve on the pum ing stroke of saidpiston.

18. A charge orining device for internal combustion engines comprising,a mixture passage, means for supplying fuel and air thereto and a pumpfor supplying additional fuel thereto during the acceleration eriod, asecondary air passage supplying a ditional air to the mixture passage,an air throttle for controlling the flow of said additional air, saidpump comprising a piston connected to the air throttle, a cylinder inwhich said pis- -ton is received and having a fuel delivery outlet,avalve for closing the delivery outlet, means operated b the pump pistonfor opening said valve an means for c osing the valve when the iston isat rest.

19. A c arge forming device for internal combustion engines com rising,a mixture passage, means for supp ying fuel and air thereto and a pumpfor sup lying additional fuel thereto during the acce eration riod, asecondary air passage supplying a ditional air to the mixture passage,an air throttle for controlling the flow of said additional air, saidump comprising a piston connected to the air throttle, a cylinder inwhich said piston is received and having a fuel delivery outlet, a valvefor closin the delivery outlet, means operable by t e pressure of thepump iston on rapid opening movements thereo for o 'enin said valve, andmeans for holding t e va ve'closed with sufiicient force to prevent theopening of the valve on slow movements of the valve when the pressureexerted by the piston on the valve opening means is low- 20. A chargeforming device for internal combustion engines comprising, a mixturepassage, means for supplying fuel and air lying additional fuel theretoduring the acce eration riod, a secondary air passage supplying aditional air to the mixture passage, an air throttle for controlling theflow of said additional air, said pump comprising a piston having arecess therein and connected to the air throttle for movement therewith,a cylinder in which the piston is slidable .and provided with a fueldelivery outlet, a valve for closing said outlet, an auxiliary pistonslidable in said recess and connected to the valve whereby the valve isoperated by said auxiliar piston.

21; A charge forming device orinternal combustion engines comprising, amixture passage, means for supplying. fuel and air thereto and a pumpfor supplying additional fuel thereto during the acce eration period, asecondary air passage supplying additional air to the mixture passage,an air throttle for controlling the flow of said additional air, saidpump comprising a piston having a re-' cess therein and connected to theair throttle for movement therewith, a cylinder in which the piston isslidable and provided with a fuel delivery outlet, a valve for closingsaid outlet, an auxiliary piston slidable in said recess and connectedto the valve sufiicient clearance being provided between the auxiliarypiston and the wall of the recess to permit slow movements of the pumpiston without accompanying movement 0 the valve operating piston undercertain operating conditions.

In testimony whereof I hereto aflix my signature.

FRED. E. ASELTINE.

